Compared with its M20 predecessor, the M50 features twin camshafts and 4 valves per cylinder. The M50 uses an iron block with an alloy head.[1] In 1992, variable valve timing (called VANOS by BMW) was introduced.
The E36 M3 was powered by the S50 engine series, which is based on the M50.

Models

Engine

Displacement

Power

Torque

Redline

Bore

Stroke

Year

M50B20

1,991 cc (121 cu in)

110 kW (150 hp) @ 6000

190 N·m (140 lb·ft) @ 4700

6750

80mm

66mm

1990

M50TUB20

110 kW (150 hp) @ 5900

190 N·m (140 lb·ft) @ 4200

6750

80mm

66mm

1993

M50B24

2,394 cc (146 cu in)

138 kW (185 hp) @ 5900

235 N·m (173 lb·ft) @ 4700

6550

84mm

72mm

1991

M50B25

2,494 cc (152 cu in)

141 kW (189 hp) @ 6000

245 N·m (181 lb·ft) @ 4700

6500

84mm

75mm

1990

M50TUB25

141 kW (189 hp) @ 5900

250 N·m (180 lb·ft) @ 4200

6500

84mm

75mm

1992

S50B30

2,990 cc (182 cu in)

210 kW (280 hp) @ 7000

320 N·m (240 lb·ft) @ 3600

7280

86mm

86mm

1992

S50B30US

179 kW (240 hp) @ 6000

305 N·m (225 lb·ft) @ 4250

6500

86mm

86mm

1993

S50B32

3,201 cc (195 cu in)

236 kW (316 hp) @ 7400

350 N·m (260 lb·ft) @ 3250

7600

86mm

91mm

1995

M50B20

The 1,991 cc (121 cu in) M50B20 was introduced with the 1990 520i. It has an 80 mm bore and 66 mm stroke and produces 110 kW (150 hp).[2]
Applications:

M50B24

This
is a 2.4 L engine based on the 2.5 L M50B25, with a reduced stroke.
This engine is only fitted to Complete Knock Down kits assembled in
Thailand. Power output is 188 hp (140 kW) and torque is 134 lb·ft
(235 Nm).Applications:

S50

The S50 is higher performance version of the M50 which was used in the M3.

S50B30

The S50B30 is a 2,990 cc (182 cu in) higher output version of the M50 which powered the E36 M3 (except in North America). It produces 210 kW (282 hp), has a bore of 86 mm (3 in) and a stroke of 86 millimetres (3.4 in).[3] The limited edition "M3 GT" model from 1995 had different tune and produced 216 kilowatts (290 hp).[4]
Applications:

S50B30US

S50B32

In 1995, the 3,201 cc (195 cu in) S50B32 replaced the S50B30 (except for North American models, which used the lower output S52).[6]
This engine produces 236 kW (316 hp). The compression ratio is 11.3:1,
the bore is 86.4 mm (3.4 in) and the stroke is 91 mm (3.6 in).[7]
Applications:

Wednesday, August 15, 2012

Listing this car today for a very good friend of mine, this has been his
pride and joy for the past 3.5 years. This car has been absolutely 100%
reliable since the S50 swap and has seen many miles up and down this
fine state. This car was professionally engine swapped at TNG Automotive
when they were located in La Crescenta, CA. No corners were cut and
anything that needed to be replace WAS replaced at the time of the swap.
Unfortunately priorities change and sometimes you've just got to let
things go. This is an original California car with a clean title in
hand. This car is ready to just get in and DRIVE.

The dirt: Is this car a show winner? No. This car is clean for its age
and is a DAILY DRIVER. The Brilliantrot paint still shines well but does
require a nice coat of wax every 2 months or so to keep it looking
good. The car has a couple bumps and dings but nothing too major. There
is some clearcoat peeling on the rear bumper
and top of the right side C-pillar. Unfortunately the dashboard cracked
over the winter so it is no longer perfect. There is a small rip in the
carpet to the right of the driver's seat. I believe the previous owner
had a Husco armrest and removed it. Pleas note that this car is not BAR
certified and currently has NO catalytic converter installed. We can
discuss details of handling the smog if the buyer is located in
California.

And you get a good M54B30 engine and install crankshaft, rods and pistons into
your M50/M52 block and you will have 3.0L engine with 10.3:1 compression
ratio. Then add s50/s52 camshafts and you will have S50us clone. Use
your Red label ecu with early non EWS M3 chip. Or contact me via private message for proper tune, sense I am the first person to do this and also I am a ECU tuner.

I decided to build a 3.0L M50 engine and bought M54B30 short block to create a S50 clone.

Modified M50 baffle plate to clear longer stroke, or just use M52/S52 baffle

Connecting rods are the same part number and lenght on all 2.8L 3.0L 3.2L BMW engines 1996 to 2006, they are all 135mm lenght.

Summary

Keep orig m50 block
Use M54B30 crankshaft, bearings(if still good), connecting rods and piston
Reuse M50 NV head
Reuse m50 exhaust and intake cams or use 2 NV intake cams
Get a chip from you for my original ecu

330 M54 crankshaft is exacly the same as M3 S52 crankshaft

M54B30 crankshaft is the same as S52B32, rod lenght is the same on your 95 m3
as M54B30, You can use your S50 crankshaft and rods and put on M52 2.8L
pistons into M50 block and that is called 2.9L high compression
stroker.

NV Pistons are heavy and bulky, M54b30 pistons are light and strong and have thin piston rings they are modern.

I would stay with M54b30 rotating assembly it is the most practical,
modern, does not cost much more, all balanced from factory, you don't
have to waste time.
Best and cheapest combination is M54B30, I would not even think about any other combination

Now you can decide on what camshafts you want to use, if you want to have the same power curve as S50 engine then just get some S50/S52 camshafts for your build.

If you want to have more power than S50 engine from 1000 to 6000 rpm
then get M54B30 intake camshaft(240 duration, 9.7mm lift you must
shorten the vanos gear 4mm with grinder on the cam) and just reuse your
M50 exhaust camshaft.

Try to get camshaft trays with lifters and matching bearing caps from
M52/S52/M54 engines, they have smaller lighter lifters and you need
these trays if you want to run M54 cam or S52 camshafts.

Photo of M54b30 intake camshaft, sprocket, anti rattle washer, installed
into M50 head. Do not remove the vanos gear from the cam, just use a
grinder and shorten the gear 5mm. I used M54B30 sprocket with all the
hardware because it is lighter than M50 and uses anti rattle spring
washer instead of just heavy washer or later model tripple washer. The
lighter the better.

Update Jun 2012 My BMW still runs great with this S50 clone, plenty of power and I love it.

I was able to turn the OBD2 dme into OBD1 by programming it.
Now for someone who buys a full m52 engine and wants to stroke it to 3.0L using this method, then install it in OBD1 car:
Tune is stock official BMW software used on the testing track.
Basicly turnes OBD2 ecu into OBD1

DME features:
1. No EWS. Works with your existing module or without the module, so no EWS drama.
2. No secondary air pump system(pump,valve,solenoid,relay)
3. No post catalyst 02 sensors, you can leave them there or take them out
4. No need to have catalitic converters
5. No fuel tank pressure sensor, no spare tire tank vent valve, you can
leave both there or remove them. This ecu uses only the fuel tank valve
near the front strut tower for tank venting like obd1 bmw does.
6. No running loss valve, you can leave it like it is if you got stock
obd2 intake manifold or bypass it and use m50 intake manifold setup, it
works fine eather way.
7. Works for manual or automatic transmissions. trans ecu works fine with it. AC works. Cruise control works.
8. Does not trow check engine light, full data diagnostics only trough 20pin connector under the hood.
9. 7200 rev limit, no speed limiter
10. No core charge, keep your own worthless obd2 dme if you ever have to go to emissions testing

Sense not much information is written about OBD2 conversion into your
OBD1 project car, I decided to write what is needed and what is not when
compared to OBD1 and OBD2 conversions.
Argument: what is better the 93-95 obd1 engine management or 96-99 engine management?
If you are putting M52 or S52 into your OBD1 E36 then it would be the
best way to go with OBD2 system that came in that same donor car.
Siemens MS41.1(OBD2) DME is better and more powerful unit than Bosch
3.3(OBD1). There are many features that MS41.1 does better like: More
precise ignition timing because on M52/S52 crank sensor is mounted on
the block and reads directly off the crankshaft, while OBD1 reads the
timing from the front pulley and timing teeth are mounted on the rubber
harmonic balancer that vibrates and not better than solid tooth gear
mounted inside the engine on the crankshaft, more precise injection with
ability to turn off each injector if the coil goes bad on that cylinder
to prevent fuel flood, bigger injectors, running loss valve with remote
fuel pressure regulator, helps reduce fuel vapor and temperature,
better on board diagnostics. Quality knock sensors that never go bad.
And more…
OBD2 conversion does not cost more money than OBD1 conversion. Lets say
you bought the M52/S52 engine and want to buy all the OBD1 parts, the
first problem is knock sensors are expensive and you need two of them,
used ones are not good because most of them crack, they are very poor
quality. Plus you will need a tune for that red 413 ecu for your M52, so
just the cost of those two parts will pay for quality OBD2 dme flash
for your swap.
With a proper OBD2 MS41.1 ecu flash your OBD2 engine management will be
the same as if you were installing obd1 engine management. DME can be
programmed so that it does not look for these emissions components and
not throw a check engine light:
You will NOT need to run/have SAP air pump, nor the SAP valve, just weld
the manifolds or use block plate, or simply run aftermarket header
system.
You will NOT need to run/have fuel tank pressure sensor, nor charcoal canister valve, nor exhaust muffler flap solenoid
SAP pump purple relay will need to be there, but it already comes on the
OBD2 harness already so just keep it there, do not plug in any other
relay there or you will burn the harness.
SAP valve vacuum solenoid will need to be plugged in, but It already
comes installed on your M52 so just keep it there, if you use the M50
intake manifold then It can be flashed out of the ecu also. Plug the
vacuum line in the manifold. Remove the vacuum canister junk.
Remote fuel pressure regulator with running loss valve is a form of an
upgrade, run it if you can, it reduces the fuel temperature, and fuel
vapor bubbles, saves you fuel, or it also can be flashed out of the ecu.
You will use the OBD2 purge valve that is located under throttle body,
and just run the line to your OBD1 charcoal canister output
No need for ASC/ABS signals connected to the ECU
EWS can be turned off and you don’t need to have any of the EWS junk
components, no need to cut any wires. If you want EWS then use the EWS
junk and let it just control the starter for anti theft protection.
E30/E36 locks are not easy to crack, so the need for EWS is just an
overkill
There are few OBD2 tuners in the US, but I can only speak of what I can
tune and code, so if you have any questions please private message me. I
have plenty of OBD2 ecu units ready to roll, no need send me anything,
keep your own obd2 ecu, sell it along with the matching ews junk on ebay
and use the money to buy quality flashed ms41.1 and it almost comes out
free cost at the end.
You can just wire the OBD2 plug to your 20 pin diagnostic connector
under the hood so that you can check the codes with regular obd2
scanner, no need to run the wires all the way inside the car.
These photos are to show you what I am talking about:
EWS2 module plug, bridge starter wires if you have EWS2 E36
SAP pump relay leave it plugged in, comes on the OBD2 harness anyway
SAP valve solenoid, leave it there, just plug the vacuum port on the manifold
3 way running loss valve, it is an upgrade, run it if you can, it is small and compact, fits anywhere
Post cat. 02 sensors, you don’t need them, but if you want to run dual cats then just run them
Fuel pressure sensor, you don’t need this at all
Carbon canister valve, you do not need this, OBD1 already had the
charcoal canister in the front, and valve is mechanical integrated in
the fuel tank.
Muffler flap valve solenoid is flashed out of the ecu.
This is my testing car , with stack of OBD2 ecus ready to be custom
flashed with quality tunes. And Tuning/Flashing software. I have the
ability to flash any MS41.1 ecu to whatever tune or car, even 528i, make
ms41.1 ecu into ms41.2. As long as it says ms41.1 on the side I can do
it. MS41.2 is the ms41.1 with different software for S52, just minor
difference in the software nothing major. I can make the ms41.1 software
work same as ms41.2.

Crankshaft, rods with pistons with good piston rings, used engine bearings.
Very good condition no scratches. even the used engine bearings can be
reused. No need to spend extra money. Stroke your 2.5L today and make
more power.

Paypal: $650 shipped to 48 states,
If you will pay with money order $620 shipped to 48 states SOLD SOLD SOLD

This will also work on all M50/M52 engines and installs without any machining and gives you 3.1L "3051cc dynamic" displacement resulting in similar power output as S50 engine.

Could this also be done with an M52B25 or M52B28 block?
Yes.

M52B28 has same bore but longer stroke than M50B25/ M52B25

Dual vanos setup from M54 will fit M50 head but it needs some
modification to fit, very minor, some aluminum welding required also

Question: i'm planning on replacing my M50b28 internals and do what is explained here in this article. but can anyone explain the modifications that need to be done to make
the vanos unit from the M54 fit into the M50 head? anybody got pictures
for it?

OP Reply: On the exhaust
side of the head, the last stud has to be re-drilled and re- tapped or
simply removed , one stud won't hurt, And then use ultra gray silicone
to seal the vanos to the head.
On the same spot where there is exhaust camshaft sensor on the dual
vanos unit, the M50 head will need to be machined using dremel tool,
then a small spot of aluminum weld needs to be welded on the M50 head
and then resurfaced to create sealing pad. Not hard to do if you got
someone who can weld aluminum. Rest of the dual vanos parts will fit the
M50 head without problem.
But there is no benefit of having dual vanos at all. Dyno results who that there is no horsepower gain from using dual vanos vs. single vanos.

Question: I would still like some more info on how to run the M54 intake cam. It would save me some good money instead of buying S50 cams.

OP Reply:

Question: Could I use an s50 rotory assembly in an m50 block?

OP Reply: Yes, but you would have to bore it out, which would probably make it not
worth it. It's cheaper just to buy the whole S50 block and use the M50
head, which is the same.

OP: whats going on man, my name is omar and im soon moving to phoenix
arizona, now let me get to my point..i dont want to be a bother to you
or anything but im really interested in doing the m50 stroker, i have a
spare m50 motor with m50 head. im missing a vanos on the spare motor i
sold the vanos a while ago so i guess im just going to use the vanos i
have in the daily driver car i have(325is). now my main question is,

1)is the m54b30 crank a direct fit?(yes)
2)are the m54b30 pistons a direct fit?(yes)
3)do i need e34 oil baffle?(no, get S52 oil baffle or mod the M50 baffle)
4)what oil pump do i need to use?(stock M50 with lockthread)
5)what crank pulley do i use?(stock M50)
6)can i use my light weight 8lb flywheel from my 325is?(it will bolt on)
7)can i use s50exhaust cam?(yes)
8)can i use zhp intake came?(yes, but might as well get S50/S52 set then)
9)what exact cam trays do i need to use(or do u recommend) for the exhaust and intake ? along with lifters and bearing caps(any M54/S52)
10)my main concern-what exactly do you have to shorten in the vanos
gear? can you please specify with specific detail(anything that cuts
metal will work)
11)what did you use to clean the motor like the way you did lol( engine
degreaser then lots of brushing, then pressure wash it then hit it again
with purple gunk detergent, let it dry, then use engine paint)

BTW im really sorry if im bothering you at all, if you dont want to help
me out its ok, i do understand the whole concept of exactly what you
did with the stroker but i just wanna get it right the first time so
thats why im PM'ing a bunch of annoying questions.
once again sorry for the noobness

PS: it is not a stroker, it is more of a S50 clone or M50/M54 3.0L mestizo

It won't be M50 anymore because M50 came in 2L and 2.5L displacement. In USA only in 2.5L.

For this "S50" clone you buy all aftermarket parts as if it is true S50

Many people don't know that S50(in usa) and 1993-1995 M50 is basicly the same engine and all aftermarket parts will bolt
on. And M52 is basicly the same as S52. This was talked over and
writen over and over again but you just can't explain it to noobs! Power
of a badge, the M3 that is in the USA market is not true M3 it is just
325is with more displacement and few more minor upgrades. True M3 is in
europe with beast of an engine, too much power for US market. But
germans knew that average american is a drug addict so they can get away
with just putting in stroked M50 engine slapping on M3 badge on the trunk lid and make americans pay more for the same...

Yes I have put the 1996-1999 valve cover and coils on it. I found a very
good deal on valve cover, M power cover and coils, the guy was local
and tought he needed those flaky M50 valve covers when converting to
OBD1 so I took advantage of it and bought it all from him for $80 now my
M50 "aka S50 clone" looks mole like "S52 clone", the more you know the
cheaper you can make your BMW look cool. This is why lots of BMW
fanatics hate me here, they don't want me to spill the secrets to the
noobs.

Vanos gear that is bolted to the camshaft has to be shortened 4mm as you
can see in the photo fresh grinding marks. Ones you compare your stock
cam with m54 cam you will know what I am talking about.

m52b28
Bore: 84mm
Stroke: 84mm
http://www.blogger.com/blogger.g?blogID=3521687182878461882#editor/target=post;postID=8781159684830874904
The s52 crank provides 89.6mm stroke in its engine, i believe its the same as m54 crank

Since effectively the s52 is a bored out and stroked m52 the rods and
crank from a s52 or m54 should actually fit without any modification
needed to the oil pan. In the end you will end up with the same 3.0-3.1L engine if you were to do it to a m50.

Im still trying to find more information so if anyone knows any reasons
why this wouldnt work in a m52 engine that would be great. The bores for
the m50 m52 and m54 are all 84mm so i dont think there should be any
issues.